It's worrying to see you continue receiving voicemail messages not intended for you and that you're unable to delete them. We are here to help. Could you please try deleting these messages while being disconnected from Wi-Fi? Do you know if the calls you're receiving are trying to reach your number or a different number? If these calls are being made to a different number, are you familiar with this number? This last question will help us identify if the calls being made to the other number are being forwarded to yours.